Combustion chamber assembly

ABSTRACT

In a combustion chamber arrangement, especially an annular combustion chamber arrangement for a gas turbine, one or more burners has, at its mouth, a deflecting device by which a combustion chamber arrangement is deflected. This achieves the effect of acoustic detuning, whereby the formation of a combustion oscillation is suppressed.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/DE99/01169 which has an Internationalfiling date of Apr. 19, 1999, which designated the United States ofAmerica.

FIELD OF THE INVENTION

The invention relates to a combustion chamber arrangement with acombustion chamber in which a burner is arranged. The combustion chamberis especially an annular combustion chamber of a gas turbine.

BACKGROUND OF THE INVENTION

DE 195 41 303 A1 discloses a combustion chamber arrangement of a gasturbine into which a number of burners open. The gas turbine has aturbine shaft with a main axis. Each burner is directed along a mainaxis. To achieve particularly high efficiency, the main axis of eachburner is tilted with respect to the main axis of the turbine shaft forproducing a swirl of a working medium. Such a tilting of the burnersdispenses with the need for a swirl-producing structural part.

In DE 43 39 094 A1 there is a description of a method of dampingthermoacoustic oscillations in the combustion chamber of a gas turbine.In the combustion of fuels in the combustion chamber of an industrialgas turbine, an aircraft engine or the like, the combustion processescan cause instabilities or pressure fluctuations which, underunfavorable conditions, induce thermoacoustic oscillations, which arealso referred to as combustion oscillations. These not only represent anundesired source of noise, they also lead to inadmissibly highmechanical loads on the combustion chamber. Such a thermoacousticoscillation is actively damped by the location of the fluctuation inheat release associated with the combustion being controlled byinjecting a fluid.

U.S. Pat. No. 4,967,562 discloses a turbine engine in which particularlygood fuel distribution in the combustion air is achieved. This isrealized by fuel being injected from a nozzle onto a baffle plate. Asthis happens, the fuel is finely atomized and is well distributed in thecombustion air which is flowing past the baffle plate.

DE 196 15 910 A1 discloses a burner arrangement, especially for a gasturbine. At least two groups of burners are provided, in each casecomprising at least one burner of the same size and geometry for fittingout a combustion chamber. At least one group of burners represents themain burners. The other group of burners is designed as a group ofdisturbing burners, each of the disturbing burners being inclined withrespect to a main burner such that a flame disk formed by the mainburner is disturbed in its homogeneity and symmetry. In this way,pressure pulsations can be avoided.

SUMMARY OF THE INVENTION

The object of the invention is to specify a combustion chamberarrangement which has favorable characteristics, especially with regardto the avoidance of thermoacoustic oscillations.

This object is achieved according to the invention by a combustionchamber arrangement with a combustion chamber which has a combustionchamber axis and in which there is arranged a burner which has anopening for a combustion gas stream to flow into the combustion chamberalong an opening direction, a deflecting means being arranged in theregion of the opening for deflecting the combustion gas stream into aninflow direction which differs from the opening direction and the inflowdirection being defined as a unit vector, with a reference point in theopening and a unit length, by three component vectors:

a) an axial component, which is parallel to the combustion chamber axis,

b) a planar component, which is perpendicular to the combustion chamberaxis and lies in a connecting plane which is defined by the referencepoint and the combustion chamber axis,

c) an orthogonal component, which is perpendicular to the combustionchamber axis and to the planar component.

In such a combustion chamber arrangement, the location of the combustionof the combustion gas flowing out of the burner is shifted by thedeflection of the combustion gas stream with the aid of the deflectingmeans. Such shifting has the consequence that the distances between thelocation of the combustion and the combustion chamber wall change. As aresult, the acoustic system which is formed by the burner and combustionchamber is acoustically detuned. By suitable alignment of the deflectingmeans, i.e. by suitable selection of the deflecting direction, theformation of a thermoacoustic oscillation can consequently besuppressed.

The combustion chamber is preferably rotationally symmetrical about thecombustion chamber axis.

The orthogonal component preferably has a length different from zero. Anorthogonal component of the inflow direction different from zero meansthat the direction of the inflowing combustion gas stream does not liein the connecting plane, i.e. the inflow direction is turned withrespect to the combustion chamber axis. Such oblique flowing in makesshifting of the location of the combustion possible in a particularlyefficient way, so that formation of a thermoacoustic oscillation issuppressed.

A further burner is preferably provided, which further burner has anopening for a combustion gas stream to flow into the combustion chamberalong a further inflow direction, which further inflow direction isdefined as a unit vector, with a further reference point in the openingof the further burner and with the unit length, by three furthercomponent vectors:

a) a further axial component, which is parallel to the combustionchamber axis,

b) a further planar component, which is perpendicular to the combustionchamber axis and lies in a further connecting plane, which is defined bythe further reference point and the combustion chamber axis,

c) a further orthogonal component, which is perpendicular to thecombustion chamber axis and to the further planar component.

The axial component preferably has a length different from the furtheraxial component. The different lengths of the axial components of thetwo burners have the consequence that the respective inflow directionsof the two burners are inclined or tilted differently with respect tothe combustion chamber axis. Such a different inclination of the inflowdirection has the effect that the locations of the respective combustioncan be set in relation to one another such that combustion oscillationsemanating from these locations disturb or even eliminate one another. Inparticular, such an arrangement can be used for a combustion chamberwith a multiplicity of burners. In this case it is possible for only twoburners or else more than two burners to be tilted differently withrespect to the combustion chamber axis. Depending on the geometricaldesign of the combustion chamber, it is also advantageous to tilt mostof the burners or all the burners differently with respect to thecombustion chamber axis.

Tilting of a burner or plurality of burners with respect to thecombustion chamber axis, manifested by a different length of the axialcomponent of the burners, may also be combined with turning. Suchturning corresponds to an orthogonal component different from zero asalready referred to above The possibility of simultaneous turning andtilting provides a wide range of possible selections for the shifting ofthe location of the combustion. This results in a multiplicity ofconfigurations, from which it is possible to select one which ensuresacoustic detuning of the acoustic system comprising the combustionchamber and burner, i.e. with which particularly great suppression ofthermoacoustic oscillations is achieved. Such a selection may be made,for example, by trying out various configurations and selecting the onewith the best thermoacoustic characteristics.

A further deflecting means, for deflecting a combustion gas streamemerging from the further burner into the further inflow direction, ispreferably provided in the region of the opening of the further burner.

A combustion of the combustion gas stream from the burner in an energycolumn and a combustion of the combustion gas stream from the furtherburner in a further energy column can preferably be produced, whichenergy columns respectively represent an extension of the combustion gasstream, with the orthogonal component and the further orthogonalcomponent being of such a magnitude and such an orientation that theenergy column from the burner and the energy column from the furtherburner overlap. An energy column is formed by the combustion of thecombustion gas stream emerging from the burner, representing one column.Such an arrangement of mutually influencing combustions from two burnersleads to a particularly efficient suppression of thermoacousticoscillations. The overlapping energy columns have the effect that thepressure and power fluctuations which originate from these energycolumns and may be the cause of a combustion oscillation also overlap.This overlapping achieves the effect of reducing or suppressing acombustion oscillation.

The deflecting means is preferably a wall protruding into the combustionchamber and surrounding the opening. It is further preferred for thedeflecting means to have a breakaway edge for swirls, which can beinduced by the combustion gas stream. Such a breakaway edge for swirlshas the effect of producing swirls in the combustion gas stream at thedeflecting means. These swirls lead to the formation at the deflectingmeans of a return flow area for the combustion gas stream, in which alocation for the combustion is stabilized. Such stabilization allowsacoustic detuning of the system to be controlled better. Moreover, fueland combustion air are mixed still further by the swirling, whichfavorably also has the additional advantage that NO_(x) emission isreduced.

The deflecting means is preferably a hollow cylinder or a hollowtruncated cone with covering surfaces sloping with respect to eachother. These covering surfaces are imaginary surfaces, that is to saynot surfaces made solidly of a material. They are formed by the edge ofthe lateral surface of the hollow cylinder or hollow truncated cone. Onecovering surface is thus the imaginary connecting surface of the edgefacing the opening and the other covering surface is the imaginaryconnecting surface of the edge protruding into the combustion chamber.This is a particularly simple and effective design of the deflectingmeans.

The combustion chamber is preferably an annular combustion chamber,especially for a gas turbine. The annular combustion chamber has acomplex geometry. In such a system, the occurrence of thermoacousticoscillations is not predictable and is especially difficult to control.Deflecting means allow even such a system to be acoustically detuned bysimple design measures with the result of suppressing thermoacousticoscillations. The annular combustion chamber preferably has amultiplicity of burners, a deflecting means being arranged in each casein the region of a respective opening for the majority of these burners,in particular for all the burners.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail by way of example and partlyschematically on the basis of the drawing, in which:

FIG. 1 shows a longitudinal section through a burner with a deflectingmeans, arranged in a combustion chamber,

FIG. 2 shows the burner from FIG. 1 with a differently designeddeflecting means,

FIG. 3 shows an annular combustion chamber of a gas turbine,

FIG. 4 shows a representation of a component breakdown for an inflowdirection,

FIG. 5 shows a representation corresponding to FIG. 4 from a differentviewing direction,

FIG. 6 shows a longitudinal section through an annular combustionchamber of a gas turbine and

FIG. 7 shows a cross section through an annular combustion chamber of agas turbine.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The same reference numerals have the same meaning in the variousfigures.

FIG. 1 shows a longitudinal section through a burner 3. The burner 3 isdesigned as a hybrid burner, i.e. it has, as a premixing stage, anannular channel 5 which concentrically surrounds a pilot burner 7. Theburner is arranged on a combustion chamber wall 9 of a combustionchamber 11. A fuel/air mixture 14A is conducted in the annular channel5. This mixture joins together with a fuel/air mixture 14B from thepilot burner 7 to form a combustion gas stream 14. The combustion gasstream 14 leaves the burner from an opening 13 a long an openingdirection 15. The opening 13 is surrounded by a hollow-cylindricaldeflecting means 17, 17A. The deflecting means 17, 17A has imaginarycovering surfaces 16A, 16B sloping with respect to each other. Thedeflecting means is consequently not rotationally symmetrical about theopening direction 15. The deflecting means 17, 17A could also have apreferential direction in cross section, that is to say not a circularcross section as in the example shown here but, for example, anelliptical cross section. It could also be a wall which does notsurround the opening 13 completely but only partially. The combustiongas stream 14 is deflected by the deflecting means 17 from the openingdirection 15 into an inflow direction 19. The deflecting means 17, 17Ahas a breakaway edge 18. At this breakaway edge 18, swirls 20 form inthe combustion gas stream 14. These swirls 20 have the effect ofproducing a return flow area for the combustion gas stream 14. This hasthe consequence that a combustion location is stabilized in these swirls20. The deflecting means 17, 17A have the effect of shifting thelocation of the combustion of the combustion gas stream 14 in relationto the combustion chamber wall 9, with respect to an inflow along theopening direction 15. Such shifting has the consequence that theacoustic system which is formed by the burner and combustion chamber isacoustically detuned. Such acoustic detuning results in a suppression ofthermoacoustic oscillations. Producing a stable combustion location withthe aid of the swirls 20 makes it easier for such acoustic detuning tobe controlled.

FIG. 2 shows the burner from FIG. 1 with a differently designeddeflecting means 17, 17B. This deflecting means 17, 17B is designed as ahollow truncated cone. It likewise has imaginary covering surfaces 16A,16B sloping with respect to each other. The advantages of thisarrangement correspond to the advantages of the arrangement from FIG. 1.

FIG. 3 perspectively shows a combustion chamber arrangement 1,comprising a combustion chamber 11, designed as an annular combustionchamber, of a gas turbine and burners 3 arranged in it along acircumferential direction. The combustion chamber 11 is rotationallysymmetrical about a combustion chamber axis 25 and has an outer wall 21and an inner wall 23. The outer wall 21 and the inner wall 23 enclose anannular combustion space 24. The inner surface of the outer wall 21 andthe outer surface of the inner wall 23 are provided with a refractorylining 27.

In FIG. 4 it is shown how the inflow direction 19, 41 can be representedas a unit vector with the unit length L by three components. A burner 3,39 has an opening direction 15, 43. A deflecting means 17, 45 deflects acombustion gas stream emerging from the burner 3, 39 into an inflowdirection 19, 41. This inflow direction 19, 41 is defined by a unitvector taken from a reference point A. The reference point A lies at thecentroid of the outer covering surface 16A lying in the combustionchamber. The unit vector has the following three component vectors:

1. An axial component 35, 36, with a length AL, BL, which is parallel tothe combustion chamber axis 25.

2. A planar component 33, 34, which is perpendicular to the axialcomponent 35, 36 and lies in a connecting plane 31, defined by thereference point A and the combustion chamber axis 25.

3. An orthogonal component 37, 38, which is perpendicular both to theaxial component 35, 36 and to the planar component 33, 34.

This orthogonal component 37, 38 is represented as a circle with across, to illustrate that the orthogonal component 37, 38 points intothe plane of the drawing.

FIG. 5 shows the burner arrangement of FIG. 4 from a viewing directionalong the combustion chamber axis 25. In this representation, theorthogonal component 37, 38 can be seen in its length OL. The axialcomponent 35, 36 points out of the plane of the drawing.

Shown in FIG. 6 is a longitudinal section through a combustion chamber11, designed as an annular combustion chamber, of a gas turbine (notrepresented specifically). In the upper half of the longitudinalsection, a burner 3 opens into the combustion chamber 11 along anopening direction 15. A combustion gas stream emerging from the burner 3is deflected into an inflow direction 19 by a deflecting means 17. Inthe case represented here, the orthogonal component 37 of the inflowdirection 19 is zero, so that the inflow direction 19 intersects thecombustion chamber axis 25 and forms an angle 46 with the combustionchamber axis 25. In the lower half of the longitudinal section, afurther burner 39 opens into the combustion chamber 11 along a furtheropening direction 49. A combustion gas stream emerging from the furtherburner 39 is deflected into a further inflow direction 41 by a furtherdeflecting means 45. In the example shown here, the further inflowdirection 41 also intersects the combustion chamber axis 25, to beprecise at an angle 48. The angle 46 of the inflow direction 19 with thecombustion chamber axis 25 is different from the angle 48 of the furtherinflow direction 41 with the combustion chamber axis 25. This isequivalent to the axial component 35 of the inflow direction 19 having alength AL which differs from that of the further axial component 36 ofthe further inflow direction 41. The burner 3 and the further burner 39consequently have inflow directions 19, 41 tilted differently withrespect to the combustion chamber axis 25. This different tiltingachieves the effect that combustion oscillations which originate fromthe respective locations of the combustion of combustion gas from theburner 3 or of combustion gas from the further burner 39 overlap suchthat the acoustic oscillations are suppressed. The case shown here,where the orthogonal component and the further orthogonal component arezero, serves only for simplified representation. The orthogonalcomponent and/or the further orthogonal component may also be differentfrom zero, which corresponds to additional turning of the inflowdirection 19 and/or of the further inflow direction 41 with respect tothe combustion chamber axis 25.

FIG. 7 shows a cross section through a combustion chamber 11, designedas an annular combustion chamber, of a gas turbine. A multiplicity ofburners 3, 39 are arranged along a circle. Each of these burners 3, 39has a deflecting means 17, 45 in the region of its opening. For everytwo neighboring burners 3, 39, the deflecting means 17, 45 are alignedsuch that the energy columns 47, 49 respectively forming due to acombustion of the combustion gas emerging from the burner 3, 39 in themanner of a column overlap in pairs. Consequently, the pressurefluctuations which occur in the energy columns 47, 49 and may be thecause of the occurrence of a combustion oscillation also overlap. Suchan overlapping has the effect of suppressing the formation of acombustion oscillations.

What is claimed is:
 1. A combustion chamber arrangement for a combustionchamber including a combustion chamber axis comprising: a burner,including an opening through which a combustion gas stream flows intothe combustion chamber along an opening direction; and deflecting means,arranged proximate to the opening, for deflecting the combustion gasstream into an inflow direction, which differs from the openingdirection, the deflecting means including a wall protruding into thecombustion chamber and surrounding the opening, wherein the inflowdirection is defined as a unit vector, with a reference point (A) in theopening and a unit length (L), by three.component vectors including, a)an axial component, parallel to the combustion chamber axis, b) a planarcomponent, perpendicular to an axis of symmetry and lying in aconnecting plane defined by the reference point (A) and the combustionchamber axis, and c) an orthogonal component, perpendicular to thecombustion chamber axis and perpendicular to the planar component. 2.The combustion chamber arrangement as claimed in claim 1, wherein thecombustion chamber is rotationally symmetrical about the burner axis. 3.The combustion chamber arrangement as claimed in claim 2, wherein theorthogonal component has a length different from zero.
 4. The combustionchamber arrangement as claimed in claim 3, further comprising a furtherburner, wherein the further burner includes an opening for a combustiongas stream to flow into the combustion chamber along a further inflowdirection, the further inflow direction being defined as a unit vector,with a further reference point (B) in the opening of the further burnerand with the unit length (L), by three further component vectorsincluding: a) a further axial component, parallel to the combustionchamber axis, b) a further planar component, perpendicular to thecombustion chamber axis and lying in a further connecting plane definedby the further reference point (B) and the combustion chamber axis, andc) a further orthogonal component, perpendicular to the combustionchamber axis and perpendicular to the further planar component.
 5. Thecombustion chamber arrangement as claimed in claim 2, further comprisinga further burner, wherein the further burner includes an opening for acombustion gas stream to flow into the combustion chamber along afurther inflow direction, the further inflow direction being defined asa unit vector, with a further reference point (B) in the opening of thefurther burner and with the unit length (L), by three further componentvectors including: a) a further axial component, parallel to thecombustion chamber axis, b) a further planar component, perpendicular tothe combustion chamber axis and lying in a further connecting planedefined by the further reference point (B) and the combustion chamberaxis, and c) a further orthogonal component, perpendicular to thecombustion chamber axis and perpendicular to the further planarcomponent.
 6. The combustion chamber arrangement as claimed in claim 1,wherein the orthogonal component has a length different from zero. 7.The combustion chamber arrangement as claimed in claim 6, furthercomprising a further burner, wherein the further burner includes anopening for a combustion gas stream to flow into the combustion chamberalong a further inflow direction, the further inflow direction beingdefined as a unit vector, with a further reference point (B) in theopening of the further burner and with the unit length (L), by threefurther component vectors including: a) a further axial component,parallel to the combustion chamber axis, b) a further planar component,perpendicular to the combustion chamber axis and lying in a furtherconnecting plane defined by the further reference point (B) and thecombustion chamber axis, and c) a further orthogonal component,perpendicular to the combustion chamber axis and perpendicular to thefurther planar component.
 8. The combustion chamber arrangement asclaimed in claim 1, further comprising a further burner, wherein thefurther burner includes an opening for a combustion gas stream to flowinto the combustion chamber along a further inflow direction, thefurther inflow direction being defined as a unit vector, with a furtherreference point (B) in the opening of the further burner and with theunit length (L), by three further component vectors including: a) afurther axial component, parallel to the combustion chamber axis, b) afurther planar component, perpendicular to the combustion chamber axisand lying in a further connecting plane defined by the further referencepoint (B) and the combustion chamber axis, and c) a further orthogonalcomponent, perpendicular to the combustion chamber axis andperpendicular to the further planar component.
 9. The combustion chamberarrangement as claimed in claim 8, in which the axial component has alength (AL) which is different from a length (BL) of the further axialcomponent.
 10. The combustion chamber arrangement as claimed in claim 9,further comprising: a further deflecting means, for deflecting acombustion gas stream emerging from the further burner into the furtherinflow direction, provided in the region of the opening of the furtherburner.
 11. The combustion chamber arrangement as claimed in claim 9, inwhich combustion of the combustion gas stream from the burner in anenergy column and a combustion of the combustion gas stream from thefurther burner in a further energy column can be produced, wherein theenergy and further energy columns respectively represent an extension ofthe combustion gas stream, with the orthogonal component and the furtherorthogonal component being of such a magnitude and such an orientationthat the energy column from the burner and the further energy columnfrom the further burner overlap.
 12. The combustion chamber arrangementas claimed in claim 8, further comprising: a further deflecting means,for deflecting a combustion gas stream emerging from the further burnerinto the further inflow direction, provided in the region of the openingof the further burner.
 13. The combustion chamber arrangement as claimedin claim 12, in which combustion of the combustion gas stream from theburner in an energy column and a combustion of the combustion gas streamfrom the further burner in a further energy column can be produced,wherein the energy and further energy columns respectively represent anextension of the combustion gas stream, with the orthogonal componentand the further orthogonal component being of such a magnitude and suchan orientation that the energy column from the burner and the furtherenergy column from the further burner overlap.
 14. The combustionchamber arrangement as claimed in claim 8, in which combustion of thecombustion gas stream from the burner in an energy column and acombustion of the combustion gas stream from the further burner in afurther energy column can be produced, wherein the energy and furtherenergy columns respectively represent an extension of the combustion gasstream, with the orthogonal component and the further orthogonalcomponent being of such a magnitude and such an orientation that theenergy column from the burner and the further energy column from thefurther burner overlap.
 15. The combustion chamber arrangement asclaimed in claim 1, wherein the deflecting means includes one of ahollow cylinder and a hollow truncated cone with covering surfacessloping with respect to each other.
 16. The combustion chamberarrangement as claimed in claim 1, wherein the deflecting means includesa breakaway edge for swirls, which can be induced by the combustion gasstream.
 17. The combustion chamber arrangement as claimed in claim 1,wherein the combustion chamber is an annular combustion chamber.
 18. Thecombustion chamber arrangement of claim 17, wherein the annularcombustion chamber is for a gas turbine.
 19. The combustion chamberarrangement as claimed in claim 17, including a multiplicity of burners,wherein a deflecting means is arranged in a region of a respectiveopening of a majority of the burners.
 20. The combustion chamberarrangement of claim 19, wherein the deflecting means is arranged in aregion of a respective opening of each of the multiplicity of burners.